Calcium phosphate plasma‐sprayed coatings and their stability: An <i>in vivo</i> study

Klein, C. P. A. T.; Wolke, J.G.C.; Blieck-Hogervorst, J.M.A. de; Groot, K. de

doi:10.1002/jbm.820280810

Cited by 129 publications

(82 citation statements)

References 6 publications

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“…The presence of the various calcium phosphates can be explained by their presence in the starting powders (see Table I), and as process-induced by-products of both the HVOF and PS coating systems. 7,8,11,[16][17][18] Analyses of the XRD results showed that the HA component of the HVOF and PS coatings had similar lattice parameters (a ϭ b ϭ 9.41Å, c ϭ 6.84 Å and a ϭ b ϭ 9.46 Å, c ϭ 6.90 Å, respectively). Curve-fitting the spectra indicated that the HVOF coatings were significantly less amorphous (p ϭ 0.05) than the PS coatings (42.5% and 55.3% ACP content, respectively).…”

Section: Resultsmentioning

confidence: 93%

“…16,[26][27][28][29] However, these coatings have not been shown to perform as consistently in vivo. 1,17,[20][21][22]30 Dalton and Cook examined the in vivo mechanical and histological characteristics of HA coated implants from several vendors. They found that, although these implants all met current FDA guidelines, there were significant differences in the interfacial shear strength and surrounding tissues.…”

Section: Resultsmentioning

confidence: 99%

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Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings

Haman

Chittur

Crawmer³

et al. 1999

J. Biomed. Mater. Res.

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Plasma spraying (PS) is the most frequently used coating technique for implants; however, in other industries a cheaper, more efficient process, high-velocity oxy-fuel thermal spraying (HVOF), is in use. This process provides higher purity, denser, more adherent coatings than plasma spraying. The primary objective of this work was to determine if the use of HVOF could improve the mechanical properties of calcium phosphate coatings. Previous studies have shown that HVOF calcium phosphate coatings are more crystalline than plasma sprayed coatings. In addition, because the coatings are exposed to more complex loading profiles in vivo than standard ASTM tensile tests provide, a secondary objective of this study was to determine the applicability of four-point bend testing for these coatings. Coatings produced by HVOF and PS were analyzed by profilometry, diffuse reflectance Fourier transform infrared spectroscopy, X-ray diffraction, four-point bend, and ASTM C633 tensile testing. HVOF coatings were found to have lower amorphous calcium phosphate content, higher roughness values, and lower ASTM C633 bond strengths than PS coatings; however, both coatings had similar crystal unit cell sizes, phases present (including hydroxyapatite, beta-tricalcium phosphate, and tetracalcium phosphate), and four-point bend bond strengths. Thus, the chemical, structural, and mechanical results of this study, in general, indicate that the use of HVOF to produce calcium phosphate coatings is equivalent to those produced by plasma spraying.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings

Haman

Chittur

Crawmer³

et al. 1999

J. Biomed. Mater. Res.

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“…It is widely known that calcium phosphate-coated implants induce faster bone adaptation and improve integration after installation [15][16][17][18][19] . Among coating techniques, the molecular precursor method 20) , in which the molecular precursor solution consisted of calciumethylenediaminetetraacetic acid/amine and diphosphate salt, was shown to be useful for calcium phosphate coating with any shape of titanium implant.…”

Section: Introductionmentioning

confidence: 99%

Tissue Response of Surface-Modified Three-Dimensional Titanium Fiber Structure

Amemiya

Fukayo

Nakaoka

et al. 2014

J. Hard Tissue Biology.

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In the present study, tissue responses of two types of three-dimensional titanium fiber structure, namely, titanium web (TWe) and titanium wire (TWi), were evaluated for external and internal bone augmentation, respectively. TWe was produced by sintering intertwined thin titanium fibers. TWi was produced by interweaving thin titanium fibers without a sintering process. The mechanical strength was superior in TWe and the formability was superior in TWi. As surface modifications of TWe and TWi, both CA coating using a molecular precursor method and immobilization of cell-adhesive protein, collagen and fibronectin, using the tresyl chloride-activated method were employed. TWe materials were implanted under the periosteum of rat calvaria to evaluate the external bone augmentation. TWi materials were implanted into the bone defect of rabbit femoral condyle to evaluate the internal bone augmentation. After 4 and 8 weeks for rat experiments with TWe materials and 12 weeks for rabbit experiments with TWi materials, new bone formation inside the porous area of the fiber structure was histologically evaluated. The bone formation rate (BFR) and the vertical bone augmentation rate (VBR) were also histomorphometrically analyzed. BFR and VBR of CA-coated TWe and TWi were significantly higher than those of non-coated TWe and TWi, respectively, for rat external and rabbit internal bone augmentation (p<0.05). BFR of collagen-or fibronectin-immobilized TWi was significantly higher than for non-coated TWi for rabbit internal bone augmentation (p<0.05), but not for rat external bone augmentation (p>0.05). In conclusion, it is suggested that surface-modified three-dimensional titanium fiber structure is a good candidate as a three-dimensional scaffold for regenerative medicine.

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“…These crystal types and the amorphous phase of calcium phosphate are more soluble than HA. 20,24,25 The crystallinity of the Correspondence to: M. Ogiso HA coating is thought to play an important role in determining the solubility of the HA coating. 26 Various approaches have been employed to improve the crystallinity of the HA coating.…”

Section: Introductionmentioning

confidence: 99%

Differences in microstructural characteristics of dense HA and HA coating

Ogiso

Yamashita

Matsumoto

1998

J. Biomed. Mater. Res.

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Two implant types of hydroxyapatite (HA) currently are available for dental implants: dense HA-cemented titanium (Ti) and HA-coated. It has been shown in previous reports that there are differences in the chemical and mechanical stabilities between the dense HA and HA coated. The differences are thought to be due to structural differences between the two ceramic types. The aim of this study was to investigate the differences in microstructural characteristics of currently available dense HA and HA coated implants before implantation and at periods of 3 weeks and 10 months after implantation in canine bone. X-ray diffractometry, infrared analysis, transmission electron microscopy, and energy dispersive X-ray analysis were used. The dense HA is composed of crystal grains, with a well crystallized structure of HA, closely bound to each other and approximately 0.4-0.6 micron in size. Implantation did not change the original sintered structure of the dense HA. The HA coating was composed of an amorphous phase with a Ca/P ratio of 1.46 and a crystal phase consisting of oxyhydroxyapatite, tricalcium phosphate, tetracalcium phosphate, and CaO, with a Ca/P ratio of 1.57. In the amorphous phase, compared to other portions in the amorphous phase, there were some layers with lower atomic density and with no significant difference in Ca/P ratio. After implantation, the crystallization of super fine crystals of approximately 4-5 nm in thickness occurred in the amorphous phase, and with time it progressed and spread from the surface to the deeper portion of the HA coating. A Ca/P ratio of 1.58 in the crystallized portion was close to the ratio (1.60) in the dense HA, suggesting that the super fine crystals were HA. This crystallization cannot significantly decrease the solubility of the amorphous phase portion and poses risks of stress accumulation within the coating and a decrease of binding strength between the HA coating and the substrate.

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Calcium phosphate plasma‐sprayed coatings and their stability: An in vivo study

Cited by 129 publications

References 6 publications

Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings

Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings

Tissue Response of Surface-Modified Three-Dimensional Titanium Fiber Structure

Differences in microstructural characteristics of dense HA and HA coating

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